ABSTRACT
In order to address these issues, pharmaceutical companies face the challenge of developing new molecules to replace the existing ones. This can be a very expensive and time-consuming process. It is now being realized that an alternative to drug development is to use the existing drugs and encapsulate them into carriers. These carriers have been termed as DDS. From a pharmacological standpoint, the aim of DDS is to transport the drug dose throughout the organism, from the site of administration to the biophase, where the drug exerts its action. In this manner, the DDS protects the drug from unwanted degradation or undesirable distribution sites. There are many classes of DDSs ranging from simple capsules (mainly made of polymers) to complex microchips (where the drug is stored in silicon microreservoirs and released on demand by an electronic signal). Most of these complex carriers are now being considered as medical devices that can incorporate different geometries and materials (Elman et al. 2009).
